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Comparative analysis of temperature and CO2 fluxes for winter wheat in Tibetan Plain and North china Plain using the EMD method

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Progress in Natural Science:Materials International 2006年第10期16卷 1066-1071页

作者： JIANG Zhaoyang, YU Qiang, LEI Shuhe, WANG Tianduo, SUN Xiaomin and ZHANG Renhua ( chinese academy of Meteorological Science, beijing 100081, china institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, china Mathematics Department, Ocean university of china, Qingdao 266071, china Shanghai institute of Plant Physiology and Ecology, chinese academy of sciences, Shanghai 200032, china) chinese academy of Meteorological Science Beijing 100081 China institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Mathematics Department Ocean University of China Qingdao 266071 China Shanghai institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai 200032 China

Comparative study of spectral properties of temperature and CO2 fluxes measured by eddy covariance method at Yucheng (36°57'N, 116°36'E, 28 m a.s.l., in the North china Plain) and at Lhasa (29°41'N, 91°20'E, 3688 m a.s. 1., on the Tibetan Plateau) is described using the empirical mode decomposition (EMD) method. The main results are: (1) The intrinsic oscillation modes or intrinsic mode functions (IMFs) were extracted from data of temperature ( T) and CO2 fluxes (F) measured at Yucheng ( T1 and F1) and Lhasa ( T2 and F2) . (2) Hilbert transform was applied to these IMF components, then the Hubert-Huang spectra and the marginal spectra of these data were obtained. (3) Comparison of temperature and CO2 fluxes in North china Plain and on Tibetan Plain illustrated that the characteristic frequencies corresponding to T1, F1, T2 and F2 are 0.05 Hz, 0.03 Hz, 0.014 Hz and 0.005 Hz, respectively.

关键词： empirical mode decomposition (EMD) intrinsic mode function (IMF) flux Hilbert transform wheat Tibet.

Azimuthal anchoring of a nematic liquid crystal on a grooved interface with anisotropic polar anchoring

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chinese Physics B 2012年第6期21卷 378-384页

作者：周璇张志东叶文江宣丽 State Key Laboratory of applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences graduate School of the chinese academy of sciences Department of Physics Hebei University of Technology

Zhang Y J et al.[Zhang Y J,Zhang Z D,Zhu L Z and Xuan L 2011 Liquid Cryst.38 355] investigated the effects of finite polar anchoring on the azimuthal anchoring energy at a grooved interface,in which polar anchoring was isotropic in the local tangent plane of the *** this paper,we investigate the effects of both isotropic and anisotropic polar anchoring on the surface anchoring energy in the frame of Fukuda et al.’s *** results show that anisotropic polar anchoring strengthens the azimuthal anchoring of grooved *** the one-elastic-constant approximation（K11 = K22 = K33 = K）,the surface-groove-induced azimuthal anchoring energy is entirely consistent with the result of Faetti,and it reduces to the original result of Berreman with an increase in polar ***,the contribution of the surface-like elastic term to the Rapini-Papoular anchoring energy is zero.

关键词： azimuthal anchoring energy surface grooves anchoring isotropy anchoring anisotropy

Gasdynamic characteristics of toroidal shock and detonation wave converging

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 739-749页

作者： TENG Honghui1,2 & JIANG Zonglin2 1. Key Laboratory of High Temperature Gas Dynamics, institute of Mechanics, chinese academy of Sci- ences, beijing 100080, china 2. graduate university of chinese academy of sciences, beijing 100039, china Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

关键词： converging, CCW relation, shock wave, detonation wave.

Differentiation transforming system

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Progress in Natural Science:Materials International 2009年第3期19卷 397-406页

作者： Qiang Chenga,b,c,*, Haibin Zhang d, Bin Wanga, Yonghua Zhao c a LASG, institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, PR china b LSEC, institute of Computing Mathematics, chinese academy of sciences, beijing 100080, PR china c SC, institute of Computer Network Information Center, chinese academy of sciences, beijing 100190, PR china d College of applied sciences, beijing university of Technology, beijing 100124, PR china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 PR China LSEC Institute of Computing Mathematics Chinese Academy of Sciences Beijing 100080 PR China SC Institute of Computer Network Information Center Chinese Academy of Sciences Beijing 100190 PR China College of applied sciences Beijing University of Technology Beijing 100124 PR China

The differentiation transforming (DFT) system is developed to produce the tangent linear codes, which is used to calculate the Jaco- bian- and the Hessian-vector products with no truncation errors. This paper first gives the introduction of the functionality and features of the DFT system, and then discusses several techniques for the implementation of automatic differentiation tools, including data depen- dence analysis, singular differentiation and code optimization. Finally, the codes generated with DFT used in several applications have been demonstrated.

关键词： Jacobian Hessian Tangent linear model Automatic differentiation

Application of asymptotic waveform approximation technique to hybrid FE/BI method for 3D scattering

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Science in china(Series F) 2007年第1期50卷 124-134页

作者： PENG Zhen1,2,3 & SHENG XinQing2 1 institute of Electronics, chinese academy of sciences, beijing 100080, china 2 Department of Electronic Engineering, beijing institute of Technology, beijing 100081, china 3 graduated university of chinese academy of sciences, beijing 100039, china institute of Electronics Chinese Academy of Sciences Beijing 100080 China

The asymptotic waveform evaluation （AWE） technique is a rational function approximation method in computational mathemetics, which is used in many appllcations in computational electromagnetlca. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral （FE/BI） method is firstly Inveetlgeted. The formuletlon of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numarlcel results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backecatter radar-cross-section （RCS） by complex targets.

关键词： hybrid FE/BI AWE electromagnetic scattering RCS

The Multifractal Analysis of the Occupation Measure of a Lévy Process

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Wuhan university Journal of Natural sciences 2000年第3期5卷 253-256页

作者： Hu Xiao\|yu institute of applied Mathematics, chinese academy of sciences, beijing 100080, china institute of applied Mathematics Chinese Academy of Sciences Beijing 100080 China

We introduce the results on the multifractal structure of the occupation measures of a Brownian Motion, a stable process, a general subordinator and a stochastic process derived from random reordering of the Cantor se... 详细信息

关键词： occupation measure Levy process Brownian motion stable process subordinator

Convergence analysis of the adaptive finite element method with the red-green refinement

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Science china Mathematics 2010年第2期53卷 499-512页

作者： ZHAO XuYing 1, 3 , HU Jun 2,? & SHI ZhongCi 1 1 State Key Laboratory of Scientific and Engineering Computing, institute of Computational Mathematics and Scientific/Engineering Computing, academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100190, china 2 Key Laboratory of Mathematics and applied Mathematics (Peking university), Ministry of Education and School of Mathematical sciences, Peking university, beijing 100871, china 3 graduate university of chinese academy of sciences, beijing 100190, china State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science /EngineeringComputing Acade Chinese Academy of Sciences graduate Unive

In this paper, we analyze the convergence of the adaptive conforming P 1 element method with the red-green refinement. Since the mesh after refining is not nested into the one before, the Galerkin-orthogonality does not hold for this case. To overcome such a difficulty, we prove some quasi-orthogonality instead under some mild condition on the initial mesh (Condition A). Consequently, we show convergence of the adaptive method by establishing the reduction of some total error. To weaken the condition on the initial mesh, we propose a modified red-green refinement and prove the convergence of the associated adaptive method under a much weaker condition on the initial mesh (Condition B).

关键词： red-green refinement adaptive finite element method convergence non-nested local refinement

Digitally determining forest inventory units with an ecological classification system

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Science china(Technological sciences) 2006年第z1期49卷 118-127页

作者： TANG Una, WANG Qingli, Guofan Shao, DAI Limin, WANG Shunzhong, LI Xiufen & XU Dong institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china graduate university of chinese academy of sciences, beijing 100101, china Department of Forestry and Natural Resources, Purdue university, West Lafayette, IN 47907, USA institute of applied Ecology Chinese Academy of Sciences

Management-level forest resource data in china were obtained with a combination of two forest inventories. However, inconsistencies in the spatial attributes of forest data vary between the two inventory types and between two inventories of the same type. The inconsistencies make it inconvenient for long-term forest management planning with digital technologies. Ecological Land Types (ELTs) and Ecological Land Type Phases (ELTPs) have been mapped in selected forestry regions in northeast china, where important forest industries are located. The boundaries of ELTs are determined by geomorphic conditions, which are quantified by Digital Elevation Models (DEM); ELTPs are classified by overlaying ELTs with forest vegetation data layers that are obtained with both remotely sensed and ground data. The ELTPs represent the divisions of land in terms of both natural and human-induced forest conditions, and therefore they are reliable units for forest inventories and management. This paper introduces a case study for digitally determining forest inventory units in Benxi City, Liaoning Province, northeast china. The general objective of the study was to explain how a compatible forest inventory system should be designed and why the compatible forest inventory system was significant to digital forestry in china.

关键词： forest inventory, ecological classification, ELT mapping, ELTP mapping, geographic information systems, forest management.

Quantifying soil erosion with GIS-based RUSLE under different forest management options in Jianchang Forest Farm

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中国科学：技术科学英文版 2006年第z1期49卷 160-166页

作者： ZHANG Hengming, WANG Qingli, DAI Limin, Guofan Shao, TANG Una, WANG Shunzhong & GU Huiyan institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china graduate university of chinese academy of sciences, beijing 100101, china Department of Forestry and Natural Resources, Purdue university, Lafayette IN47901, USA Northeast Forestry university, Harbin 150040, china institute of applied Ecology Chinese Academy of Sciences graduate university of chinese academy of sciences

Quantitatively estimating soil erosion with an integration of geographic information system (GIS) and the revised universal soil loss equation (RUSLE) under four different exposed soil proportion scenarios caused by forest management practices was studied at Jianchang Forest Farm. The GIS provided means of input data generation required by RUSLE model and allowed a spatial assessment of the erosion hazard over the study area. Four exposed soil proportion scenarios of 5%, 10%, 20% and 30% were tested with the GIS-based RUSLE model to evaluate soil erosion hazard. The predicted soil erosion potentials were classified into five categories in order to provide valuable aids for management planning.

关键词： geographic information system, RUSLE, soil erosion, forest management.